The invention relates to a device for sealing pressure compensation openings in accordance with the preamble of Patent claim 1.
As a rule, electronic control units are built into a housing in order to protect them against external influences. The requirements imposed on this housing are particularly high when it is used in a motor vehicle. On the one hand the housing must have so-called pressure compensation openings at which pressure compensation can take place between the interior of the housing and the surroundings, and on the other hand for these components the housing must prevent water from entering so that the electronic circuit is reliably protected against damage caused by water or moisture. This is achieved at the present time by providing small holes acting as pressure compensation openings in the housing, which as a rule is made of metal or a hard plastic material, thus allowing air to circulate. In order to protect against water, these holes are closed from within by attaching an adhesive gas-permeable and watertight piece of sheeting known, for example, under the name of Goretex or Sympatex. Because this watertight and gas-permeable material is very expensive, the pressure compensation openings are covered over as small an area as possible. Therefore, the watertight and gas-permeable piece of sheeting is placed in the interior so that it cannot be removed unintentionally. This state of the art is shown in FIG. 1 where the electronic device is contained in the two-part housing 7. The one housing part 10 is pot-shaped and generally made of a plastic material while the other housing part 11 acts as a cover at the top or bottom. This housing part is made of metal and is equipped with means for attaching to the motor vehicle.
The label 1 with inscription 2 and barcode 3 is affixed by adhesion to the housing 7, in particular to the pot-shaped housing part 10. The housing 7 itself is attached by screws. Alongside the label, the pressure compensation openings 4 can be seen which are sealed from within over as small an area as possible by means of the gas-permeable and watertight piece of sheeting 5. The illustration shows the entire piece of sheeting at this point, although in fact it is situated on the inside of the housing, in particular in the interior of the pot-shaped housing part 10.
A disadvantage here, however, is that an additional working step is needed for sealing the pressure compensation openings with the adhesive gas-permeable and watertight piece of sheeting. Another disadvantage is due to the fact that this step in the process cannot be reliably monitored and inspected.